Shelly Cashman Series Discovering Computers 2003

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• Power Supply, Fan
• Motherboard
• CPU, Co-processor
• Heat Sinks
• Memory Chips (RAM,ROM,CMOS)
• Expansion Slots/Expansion Cards
• Sound Card, Network Card, Video Card, Video
  Capture Card
• System Clock
• Buses (System and Expansion(ISA,PCI,AGP, USB and
  1394 bus)
• Ports (back side of system unit)
• Serial, Parallel, Video,USB, USB 2.0,Midi, SCSI,
  Wireless,1394 or FireWire
• keyboard/Mouse, Hard Drive, Monitor, Printer,
  other external devices
• Hard Drives, Floppy Drives, Cables
• Glue Chips

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CPU
CPU

• Chip a small piece of semi conducting material
  that integrated circuits are etched. An
  integrated circuit is a pathway capable of
  carrying electrical current and contains millions
  of transistors or gates that open or close the
  circuit for the signal
• One of the most important ones is the CPU

4044 Chip
8088 Chip 5 MgHz
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Central Processing Unit

• What is the central processing unit (CPU) ?

• Interprets and carries out basic instructions
  that operate a computer
• Also calledthe processor

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Common Processors Intel, AMD, IBM and Motorolla

• Server Processors
• Xeon MP, Itanium2, Pentium, Opteron, Athlon
• Desktop Processors
• Pentium D with Dual Core Processor, Pentium4
  (with HT technology), Celeron, Duron,PowerPC
• Mobile Processors
• Pentium Duo, Celeron M, Pentium M, Mobile
  Athlon, Duron

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Central Processing Unit

• What are the components of the CPU?

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Central Processing Unit

• What is the control unit?

• Directs and coordinates operations in computer

Control unit repeatsfour basic operations

• Fetch - obtain program instruction or data item
  from memory
• Decode - translate instruction into commands
• Execute - carry out command
• Store - write result to memory

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Central Processing Unit

• What is a machine cycle?

• Four operations of the CPU comprise a machine
  cycle
• Also called instruction cycle

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Central Processing Unit

• What is the arithmetic/logic unit (ALU) ?

• CPU component that performs execution part of the
  machine cycle

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Central Processing Unit

• What is pipelining?

• CPU begins executing second instruction before
  completing first instruction
• Results in faster processing

Machine Cycle (without pipelining)
Machine Cycle (with pipelining)
Instruction 1 Instruction 2 Instruction
3 Instruction 4
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Central Processing Unit

• What is a register?

• Temporary storage area that holds data and
  instructions

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Central Processing Unit

• What is the system clock?

• Synchronizes all computer operations
• Each tick is clock cycle

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Central Processing Unit

• How do personal computer processors compare?

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Data Representation

• Two states
• Binary numbering system
• ASCII (American Standard Code for Information
  Interchange)
• EBCDIC (Extended Binary Coded Decimal Interchange
  Code)

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Data Representation

• What are two popular coding systems to represent
  data?

• ASCII - American Standard Code for Information
  Interchange
• EBCDIC - Extended Binary Coded Decimal
  Interchange Code

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Data Representation

• How is a character sent from keyboard to computer?

Step 1 Press letter T
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Memory

• What is memory?

• Temporary storage area for operating system,
  application programs, and data
• Consists of one or more chips on motherboard
• Each byte stored in unique address

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Memory

• How is memory measured?

• By number of bytes available

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Memory

• What are two types of system unit memory?

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Memory

• What is random access memory (RAM)?

• Memory chips that can be read from and written to
  by processor
• Most RAM is volatile
• The more RAM a computer has, the faster it
  operates

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Types of Memory

• RAM
• Memory chips in the system unit
• Stores programs and data
• Volatile
• Dynamic RAM (DRAM), must be re-energized
• Synchronous DRAM (SDRAM) is faster because it is
  synchronized to the system clock, 7.5 ns
• DDR SDRAM, 3ns
• RDRAM (Intel and Rambus is trying to push),
  expensive, 1.25ns
• Static RAM (SRAM)
• Faster and more reliable than DRAM
• Does not have to be re-energized as frequently as
  DRAM
• Used for special purposes

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RAM

• Often smaller in size than processor chips
• Packaged on circuit boards
• SIMM (single in-line memory module) old
  technology current computers use------
• DIMM (dual in-line memory module)
• RIMM (Rambus in-line memory module
• Typically SDRAM chips

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Memory

• What is cache?

• Helps speed computer processes by storing
  frequently used instructions and data
• Also called memory cache, cache store, or RAM
  cache
• L1 cache built in processor
• L2 and L3 cache not built in processor (depends
  on currency)
• L2 advanced transfer cache most common

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Cache

• Memory cache, cache store or RAM cache
• Level 1 (L1), small capacity (8 Kb to 64 Kb),
  built directly on the processor
• Level 2 (L2), external cache, on SRAM chips,
  slightly slower than L1 cache but has a larger
  capacity, 64 KB to 4 MB, newer machines L2 cache
  is built on the processor and called Advanced
  Transfer cache- these machines can also have L3
  cache (external)
• Machines with cache (10-40 faster)
• Most current machines have 256K to 512K of cache

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Memory

• What is read-only memory (ROM)?

• Memory chips that contain data, instructions, or
  information that is recorded permanently

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Memory

• What is CMOS?

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Memory

• What is memory access time?

• Speed at which processor can access data from
  memory directly
• Measured in nanoseconds (ns), which is one
  billionth of a second

• It takes 1/10 of a second to blink your eye a
  computer can perform up to 10 million operations
  in same amount of time

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Expansion Slots and Expansion Cards

• What is an expansion slot?

• An opening, or socket, where circuit board is
  inserted into motherboard
• Expansion card inserted in expansion slot

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Expansion Slots and Expansion Cards

• How are expansion cards used?

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Ports

• What is a port?

• Connects external devices to system unit

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Ports

• What is a serial port?

• Transmits one bit of data at a time
• Used to connect slow-speed devices, such as
  mouse, keyboard, modem

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Ports

• What is a parallel port?

• Connects devices that can transfer more than one
  bit at a time, such as a printer

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Ports

• What is a universal serial bus port (USB) ?

• Connector that supports newer peripherals and
  plug and play
• Other popular ports include 1394, MIDI, SCSI, and
  IrDA

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PORTS
USB, USB 2.0 Can connect multiple devices
MIDI Connects an instrument to the system
unit SCSI High speed parallel port used to
connect disk drives, 7 devices can be
attached 1394 (Fire Wire) Can connect multiple
devices requiring fast connections Digital video
camcorders, color printers, digital cameras and
DVD drives
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• What is a bus?

• Channel that allows devices inside computer to
  communicate with each other
• System bus connects processor and RAM
• Bus width determines numberof bits transmitted
  at one time
• Word size determines numberof bits processor can
  interpretand execute at a given time

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Buses

• What is an expansion bus?

• Allows processor to communicate with peripherals

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Expansion Bus

• Expansion bus allows the CPU to connect to the
  peripheral device attached to the expansion card
• ISA (Industry Standard Architecture)
• Mouse, Modem, Soundcard
• PCI (Peripheral Component Interconnect)
• Hard Drive (4 X faster than ISA)
• AGP (Accelerated Graphics Port) which is
• actually a bus
• Bus designed for a video card (AGP video card)
• USB (Universal Serial Bus), multiple devices,
• USB connects to the PCI bus

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Market Tiers

• Top Tier
• IBM, Apple, Compaq and HP
• Second Tier
• Newer companies with high sales volume
• Gateway, Dell, Packard Bell
• Third Tier
• Smaller Start up Companies
• Mail Order

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Marketing Channels

• Computer Retail Store
• Mail Order Suppliers
• Value added Reseller
• Manufacturer Direct